So far I am really enjoying this game, there seems to be just enough to keep me occupied. So let me weigh in on some of my thoughts.

1. Customizing your Hero. Like Shield, color of armour, Helm stuff like that
2. I would like to be able to pick a Wonder to fill up that land of mine. But you have to choice carefully.
3. Customizable FLAGS. I think walking around with your own personalized flag would be very cool, and hung off your castle walls.
4. I want a to be able to capture an enemy and maybe have a chance to persuade him to join my army if not "Off with his Head"
5. Establish Trade routes between allies.... not sure if this game would allow something like that.
6. Morel Points for the Peasants. Maybe to much micromanagement but maybe it can work.
7. A corral to keep your Cows and sheep, but no Unicorns allowed
8. I haven't seen any navy stuff yet, and never got the opportunity in the beta. Hope you can get another town along the coast line.
9. Have all Unicorns banned from the game
10. Customize your Castles more, More Traps to choose from

So far the game seem to cover most of the main things, I know it is early but and there is a lot of work ahead for the devs but that is my two cents.